NBC has ditched a plan to name “To Catch a Predator” reporter Chris Hansen a lead anchor of “Dateline” following allegations he’s been having an extramarital tryst with a pretty Florida TV reporter and that he sent her explicit photos.

Sources told Page Six that Hansen was to be named “Dateline” anchor next month after current anchor Ann Curry landed the top job at “Today.” But the plan has been scrapped by NBC brass, who believe the scandal has damaged Hansen.

One source said, “Hansen was to be announced as a lead anchor now that Ann Curry has the job on ‘Today.’ While NBC is publicly playing down the scandal, it’s thrown their plans into disarray. Kate Snow may now have to get the job, but she’s been on the show only a year.”

Hansen — who nails sexual deviants on his hidden-camera “To Catch a Predator” series — was secretly filmed in a romantic tryst with TV reporter Kristyn Caddell, according to the National Enquirer.

Hansen, 52, a married father of two, has been seeing Caddell, 30, for four months and was recorded taking her to the Ritz-Carlton in Manalapan, Fla., for a “romantic dinner” before they shacked up in her Palm Beach apartment, the Enquirer reported. Cameras filmed them arriving at the hotel and driving back to Caddell’s pad, where they didn’t emerge until 8 the next morning.

Sources close to Hansen, who lives with his wife Mary, 53, and their two young sons in Connecticut, told The Post: “They’ve been friends for a long time, and there’s no truth to this. There was no romantic dinner, and he didn’t stay with her that night.”

It was later reported that Hansen sent explicit photos of himself to Caddell and is now terrified they could be leaked. Another TV source told us, “NBC and its owner Comcast are a buttoned-down group. They don’t like this type of scandal one bit.”

A rep for NBC News said, “This couldn’t be further from the truth. Ann Curry is the anchor of ‘Dateline.’ ” The rep didn’t respond when we then asked if they had planned for that to change.